♻️(backend) open tree endpoint to deleted documents only for owners

The tree endpoint will now return a result only for owners. For other
users the endpoint still returns a 403. Also, the endpoint does look for
ancestors anymore, it only stay on the current document.

src/backend/core/api/viewsets.py

@@ -851,33 +851,47 @@ class DocumentViewSet(
 
         try:
             current_document = (
-                self.queryset.select_related(None).only("depth", "path").get(pk=pk)
+                self.queryset.select_related(None)
+                .only("depth", "path", "ancestors_deleted_at")
+                .get(pk=pk)
             )
         except models.Document.DoesNotExist as excpt:
             raise drf.exceptions.NotFound() from excpt
 
-        ancestors = (
-            (
-                current_document.get_ancestors()
-                | self.queryset.select_related(None).filter(pk=pk)
-            )
-            .filter(ancestors_deleted_at__isnull=True)
-            .order_by("path")
-        )
+        is_deleted = current_document.ancestors_deleted_at is not None
 
-        # Get the highest readable ancestor
-        highest_readable = (
-            ancestors.select_related(None)
-            .readable_per_se(request.user)
-            .only("depth", "path")
-            .first()
-        )
-        if highest_readable is None:
-            raise (
-                drf.exceptions.PermissionDenied()
-                if request.user.is_authenticated
-                else drf.exceptions.NotAuthenticated()
+        if is_deleted:
+            if current_document.get_role(user) != models.RoleChoices.OWNER:
+                raise (
+                    drf.exceptions.PermissionDenied()
+                    if request.user.is_authenticated
+                    else drf.exceptions.NotAuthenticated()
+                )
+            highest_readable = current_document
+            ancestors = self.queryset.select_related(None).filter(pk=pk)
+        else:
+            ancestors = (
+                (
+                    current_document.get_ancestors()
+                    | self.queryset.select_related(None).filter(pk=pk)
+                )
+                .filter(ancestors_deleted_at__isnull=True)
+                .order_by("path")
             )
+            # Get the highest readable ancestor
+            highest_readable = (
+                ancestors.select_related(None)
+                .readable_per_se(request.user)
+                .only("depth", "path")
+                .first()
+            )
+
+            if highest_readable is None:
+                raise (
+                    drf.exceptions.PermissionDenied()
+                    if request.user.is_authenticated
+                    else drf.exceptions.NotAuthenticated()
+                )
         paths_links_mapping = {}
         ancestors_links = []
         children_clause = db.Q()

src/backend/core/tests/documents/test_api_documents_tree.py

@@ -1205,3 +1205,56 @@ def test_api_documents_tree_list_authenticated_related_team_members(
         "updated_at": parent.updated_at.isoformat().replace("+00:00", "Z"),
         "user_role": access.role,
     }
+
+
+def test_api_documents_tree_list_deleted_document():
+    """
+    Tree of a deleted document should only be accessible to the owner.
+    """
+    user = factories.UserFactory()
+    client = APIClient()
+    client.force_login(user)
+
+    parent = factories.DocumentFactory(link_reach="public")
+    document, _ = factories.DocumentFactory.create_batch(2, parent=parent)
+    factories.DocumentFactory(link_reach="public", parent=document)
+
+    document.soft_delete()
+
+    response = client.get(f"/api/v1.0/documents/{document.id!s}/tree/")
+    assert response.status_code == 403
+
+
+def test_api_documents_tree_list_deleted_document_owner(django_assert_num_queries):
+    """
+    Tree of a deleted document should only be accessible to the owner.
+    """
+    user = factories.UserFactory()
+    client = APIClient()
+    client.force_login(user)
+
+    parent = factories.DocumentFactory(link_reach="public", users=[(user, "owner")])
+    document, _ = factories.DocumentFactory.create_batch(2, parent=parent)
+    child = factories.DocumentFactory(parent=document)
+
+    document.soft_delete()
+    document.refresh_from_db()
+    child.refresh_from_db()
+
+    with django_assert_num_queries(9):
+        client.get(f"/api/v1.0/documents/{document.id!s}/tree/")
+
+    with django_assert_num_queries(5):
+        response = client.get(f"/api/v1.0/documents/{document.id!s}/tree/")
+
+    assert response.status_code == 200
+    content = response.json()
+    assert content["id"] == str(document.id)
+    assert content["deleted_at"] == document.deleted_at.isoformat().replace(
+        "+00:00", "Z"
+    )
+    assert len(content["children"]) == 1
+    assert content["children"][0]["id"] == str(child.id)
+    assert content["children"][0][
+        "deleted_at"
+    ] == child.ancestors_deleted_at.isoformat().replace("+00:00", "Z")